DESCRIPTION (adapted from the applicant's abstract: For more than 40 years, demographers, economists, historians of medicine, and public health scientists have debated the reasons for the modern decline in mortality, disagreeing over the role, magnitude, and interaction of economic growth, improvements in medical care, nutrition, public health measures, ecological changes, and private hygiene practices. Despite the importance of longitudinal analyses of population dynamics, there have been virtually no detailed studies of pre- 1940 mortality declines outside of North America, Europe, and Japan. This research seeks to address this gap in knowledge by examining Uruguay's mortality decline from 1882 to 1950. The availability of 19th century vital statistics publications, extensive social statistics, and primary archival sources in Uruguay makes it a rare population "laboratory." This study proposes to add to the understanding and methodology of mortality transitions and population aging by: 1) building upon existing studies of Uruguay's infant, sex-, and age-specific mortality by including the characteristics ethnicity, residence, occupation, and literacy and tracking changes in the distribution of the leading causes of death by age group in five-year intervals; 2) developing an integrated methodology that combines established historical demography approaches with an iterative historical-epidemiological feedback loop; and 3) testing through multi-stage regression analysis the relative impact of social inequality indicators on urban life expectancy. The investigators hypothesize that infant mortality is more closely correlated with indicators of social inequality than with absolute wage levels and that adult mortality declines accelerate after the implementation of social security measures. The results of this analysis will be useful to policy makers, scholars, and public health audiences in the U.S., Latin America, and other regions who are interested in the determinants of longevity.